Targeting Highly Branched Polyethylene Waxes by Unsymmetrical Bis(arylimino)acenaphthene‐Nickel Precatalysts Bearing Rigid N ‐Phenyl and N‐Naphthalen‐1‐yl Groups

To develop high‐performance unsymmetrical bis(arylimino)acenaphthene‐nickel precatalysts, N‐phenyl and N‐naphthalen‐1‐yl groups were strategically selected as one‐side rigid N‐aryl arm without auxiliary alkyl substituents, enabling the diverse construction of ligands ( L2 ‐ L4 and L5 ‐ L8 ) and their corresponding nickel complexes ( Ni2 ‐ Ni4 and Ni5 ‐ Ni8 ). Upon treatment with either EASC or MMAO, all nickel complexes demonstrated moderate to high activities in polymerizing ethylene, achieving up to 16.1 × 10 6 g of PE (mol of Ni) −1 h −1 , and noticeably generated branched polyethylene waxes with narrow and lower molecular weights from 1.8 kg mol −1 to 24.5 kg mol −1 . Notably, these nickel‐based catalytic systems exhibited enhanced thermostability, with an optimum operational temperature of 60°C, outperforming their previously reported nickel analogs. Critically, the strategic modification of another N‐aryl groups enabled precise tuning of catalytic performance. Specifically, varying the positional isomerism of the di(4‐fluorophenyl)methyl group not only modulated the catalytic activities of the nickel complexes but also dictated the microstructural features—including molecular weight and branching degree—of the synthesized polyethylene waxes. A systematic analysis of the structure‐performance correlations has been conducted to elucidate how the strategic incorporation of sterically demanding, multi‐substituted N‐aryl fragments—in tandem with rigid N‐phenyl or N‐naphthalen‐1‐yl substituents—modulates catalytic performance.